Ancient Guardian of Fire

Spellcasting. The Ancient Guardian of Fire is a spellcaster. Its spellcasting ability is Wisdom (spell save DC 17, +7 to hit with spell attacks). The Ancient Guardian of Fire has following spells prepared: 

• Cantrips (at will): Create Bonfire, Control Flames, Fire Bolt,
• 1st level (9 slots): Catapult, Magic Missile, Shield, Burning Hands,
• 2nd level (8 slots): Misty Step, Aganazzar’s Scorcher, Flame Blade, Flaming Sphere
• 3rd level (7 slots): Blink, Counterspell, Haste, Slow, Fireball, Fly, 
• 4th level (6 slots): Charm Monster, Dimension Door, Greater Invisibility, Summon Greater Demon, Wall of Fire
• 5th level (5 slots): Dominate Person, Far Step, Flame Strike
• 6th level (4 slots): Disintegrate, Investiture of Flame
• 7th level (3 slots): Fire Storm, Prismatic Spray
• 8th level (2 slots): Incendiary Cloud, Sunburst
• 9th level (2 slots): Prismatic Wall, Meteor Swarm

Multiattack: The Guardian makes 2 melee attacks with the fire staff.

Fire Staff: Melee Weapon Attack: +12 to hit, reach 10ft., 1 target. Hit: 19 (2d10+9) bludgeoning damage and 31 (3d12+13) fire damage.

Fire Strike: Ranged Weapon Attack: +13 to hit, range 50/80ft., 1 target. Hit: 52 (8d8+20) fire damage.

Fire Beam (Recharge 6): 100ft long 5ft wide beam of white hot fire. All creatures in the beam must make a Dexterity Save (DC17), on a failed save take 65 (8d12+17) fire damage.